C , overloding functions, templates-CodePudding

I want to ask is it possible to write overloaded function for arithmetic's type which returns double and for array-type which returns valarray. Simple example

template<typename T> 
double foo(T x) { 
  return x; 
}
 
template<typename T> 
std::valarray<double> foo(T const &arr) {
  std::valarray<double> valarr(1,1); 
  return valarr; 
}

In result I get expected message: call to 'foo' is ambiguous. Is there any possibility to write such a functions?

I would really appreciate all comments.

CodePudding user response：

For C-array types, it would be:

template<typename T, std::size_t N>
std::valarray<double> foo(T const (&arr)[N])
{
    // ...
}

CodePudding user response：

You can use C 20 concepts:

#include <valarray>
#include <type_traits>

template<typename T> 
  requires std::is_arithmetic_v<T>
double foo(T x) { 
  return x; 
}

template<typename T>
  requires std::ranges::random_access_range<T>
std::valarray<double> 
foo(T const& arr) {
  std::valarray<double> valarr(1,1); 
  return valarr; 
}